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Other Vintage Household Electrical or Electromechanical ItemsFor discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details.

Hello all. I'm about to embark on my second restoration project. I'm not sure if 1995 counts as vintage, but 1995 is when my soon-to-arrive Roland XP-50 keyboard/music workstation dates from. It was sold as a professional instrument back in the day, so is probably worth saving from landfill.

It's about as far from valve technology as it gets, being surface mount technology, but it does have a floppy drive (probably non-functional). It looks in moderate condition for a unit of its age, having the odd crack in the plastic case and a deal of grubbiness. The LCD display is totally blank, which renders the machine unusable, but there may be an easy fix for this. If anyone is interested, I'll post progress here.

Edit: Just spotted that it should be at least 25 years old to qualify, so mods please feel free to delete.

Also check the kevbed/pcb's for leaking glue. If the keybed hasn't been replaced or repaired then there s a fault with they keybeds used in a lot of higher end roland keyboards where the glue holding in the key weights breaks down dripping on to the keybed pcb. If not looked at/fixed it can irreversibly damage the keybed making it useless. There are plenty of tutorials on how to fix it online.

The floppy drive, if non-functioning will need to be a specific type iirc as it needs jumpers that are omitted from most PC drives, or replacement with the correct floppy emulator.

Many thanks for the info. I'll be sure to check these issues out when it arrives, although research suggests that while the XP-30 and XP-60 both had weighted keys, the XP-50 does not. We'll see in due course.

Yes it would seem that the XP50 is fine which must be a relief. Roland stuff is generally very reliable so I'm suspecting that it should be either a very simple problem or it's knackered.
It appears to be basically a JV-1080 in a keyboard, not something to sniff at and is certainly worth repairing.

The LCD contrast is controlled via the CPU, IC20. A PWM signal goes to IC17, and is integrated to provide a d.c. contrast control level at pin 7 of IC17; High is no contrast, Low is full contrast.

Measure this point to find out if it is simply the LCD contrast. If it is stuck high, just work back toward the CPU, varying the contrast control as needed to find out where the circuit is not playing.

If you want to force the contrast high, ground pin 3 of CN14 to enable you to evaluate the rest of the keyboard, and note any other faults.

Roland very helpfully provide decent self test routines, as shown in the service manual.

Hi Kevin. Yes, I have the manual with schematics and apparently failure in this area is almost universal due to bad surface mount electrolytics. Worst case scenario is that electrolyte has eaten away tracks and vias. What worries me more, though, is what Parceforce will have managed to do to it during shipping...

I appreciate that this bit of kit is of limited interest to most on the forum, partly because of its relative youth, but the technology used is not dissimilar to that in some other more common devices that either are, or soon will, be regarded as vintage and worth saving.

Hi,
I think I have looked at a similar model where the backup battery had failed, and one of the settings that should be saved is the lcd contrast .... so it had defaulted to a setting where you couldn't see the lcd !
I have also had a power supply board fail, this took out the main board as well. Ended up being a really expensive repair.

although I've not worked on this paticular keyboard i've repaired lots or similar vintage computing equipment (Commodore Amiga 1200/600) as you have already mentioned bad surface mount electrolitics are very likely. if you dont repair this vintage of equipment very often, one word of caution be very carefull removing the old caps as the pads can lift for fun especially if the old cap has leaked badly.

__________________
The light at the end of the tunnel is probably the headlight of an oncoming train

Well, the beast has arrived. It is as described by the seller, including a sounds expansion rom board. It's dirty and there's a crack in the casing around the floppy drive, but apart from that there is little damage visible other than a few scuffs and dings. What is particularly good news is that the display is unscratched.

The keyboard powers up. As noted by the seller, the display is blank but backlit. The unit is basically functional and sounds are produced and audible with headphones. This is a pro keyboard, so does not have built-in speakers. All the keys work, although the scale is not an equal temperament scale. I'm guessing that this will be fixed once a system reset is performed and a new backup battery is installed.

Well, now I'm in a bit of a quandary. As suspected, the memory backup battery, a CR2032, was down to 150 mV. After replacing the battery, temporarily taking the LCD contrast line to ground to see what was going on, and doing a system reset, practically everything now works, including the LCD once the contrast setting was set correctly. There is no sign of capacitor leakage. So, given the history of these units, do I recap or not?

The aftertouch seems a little weak, in that a lot of pressure is required. I've not used a keyboard with aftertouch before, so I don't know how normal it is.

The one thing that doesn't work is the floppy drive. It looks like someone might have been there before me, as the screw is missing from the bottom shielding plate. I think I'll spend some time triying to understand what's going on with this drive.

Mark -- the XP-50 default is equal temperament, but each note in the octave is adjustable in cents. Adjustments apply to each octave. Clearly it was just a memory corruption issue I was seeing.

I may replace it, Jay, but in the meantime I've repaired the original and nobody is more surprised than me! There is a largish crack in the plastic casing in which the drive is mounted, and it's clear that it received a heavy impact. On closer inspection, one of the drive mounting pillars is broken. I then took a close look at the drive's PCBs. Everything looked OK except for the main data cable connector, the joints of which didn't look brilliant. I applied flux and reflowed them all. Result: drive now working.

For the uninitiated, aftertouch is a pressure-sensitive switch strip or sensor that runs under the keys of a keyboard. Normal key playing does not activate the function but if you press the key really hard it activates it. It's used to add effects (often selectable) to the sound, such as a vibrato, a filter or similar thing that you might want at the end of a note.

So, everything is now working. The keys have all been removed, put through the dishwasher and put back. Instrument is now working perfectly. However...

I'm in two minds about replacing the SMD electrolytics, even though there is no current sign of leakage. There was a service note, only in Japanese, about the caps on the expansion cards, advising customers not to use them, so there is clearly a problem. Given that electrolyte leakage is not uncommon on these, and the damage that can result, I'm leaning towards wholesale replacement. What's the collective opinion here?

If you intend to use this for live gigs, I'd say replace them for the sake of reliability. If, on the other hand, you just want it for messing about at home, I'd use it as-is and keep a close eye on its operation and immediately investigate any strange behaviour.

Regards,
Paul

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...No, it's not supposed to pick up the World Service, it's not a radio!

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